The Earth Science Picture of the Day (EPOD) highlights the diverse processes and phenomena which shape our planet and our lives. EPOD will collect and archive photos, imagery, graphics, and artwork with short explanatory captions and links exemplifying features within the Earth system. The community is invited to contribute digital imagery, short captions and relevant links.

Etienne’s Egregious Error

In 1852, French anti-royalist Étienne Trouvelot fled Napoleon III’s France for America, settling in Medford, Massachusetts. An amateur natural scientist, he believed he could build a business and energize the silk industry by hybridizing the fragile North American silk moth (Antheraea Polyphemus) with a vigorous continental species, the European gypsy moth (Lymantria dispar dispar). He imported Lymantria dispar dispar egg masses and began interbreeding experiments in the woods behind his house. Étienne’s hybridizing efforts failed and he quickly lost interest in the project. He went on to a career in astronomical illustration and later moved back to France. Conversely, Étienne’s gypsy moths loved their new home and very rapidly spread across the northeastern United States, their territory still expanding about 12 miles (19 km) each year.

The introduced European gypsy moth is now one of the most destructive hardwood pests in North America, its prolific caterpillarlarvae spreading on the wind and voraciously consuming leaves of virtually all known hardwood trees and bushes. Economic losses and pest control costs are in the tens of millions of dollars annually. This photo is a male European gypsy moth (looking for females through my porch window) and features its prominent antennae which detect the sexual pheromones of the larger female. Life is short for these adult moths. With only a vestigial digestive system, they cannot feed and live only 5-7 days. However, during that short life they manage to mate, produce abundant egg masses, and propagate the incredible damage of Étienne’s egregious error.